Pb2+ blocks calcium currents of cultured dorsal root ganglion cells

Martyn L. Evans, Dietrich Busselberg, David O. Carpenter

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Abstract

The divalent cation lead (Pb2+) blocks sustained and transient voltage sensitive calcium channel currents of cultured rat dorsal root ganglion cells. The IC50 for inhibition of the total peak current evoked by a step depolarization from -80 to 0 mV was 0.6 μM, compared to an IC50 of 2.2 μM for Cd2+. The current activated by a depolarization from -40 to 0 mV was inhibited by 50% by 1.0 μM Pb2+. Low threshold currents activated by a step from -100 to -30 mV were blocked by Pb2+ at higher concentrations (IC50=6 μM). The block progressed in the absence of channel activation and showed little voltage dependence. Peak sodium current was reduced by 6.6% at 1 μM Pb2+ while at 20 μM the peak current was reduced by 40% with marked slowing of the time course of activation. The potassium rectifier current was reduced by 4.1% at 1 μM Pb2+. Thus, Pb2+ selectively blocks calcium currents at concentrations in the range of those causing toxicity in man.

Original languageEnglish
Pages (from-to)103-106
Number of pages4
JournalNeuroscience Letters
Volume129
Issue number1
DOIs
Publication statusPublished - 5 Aug 1991
Externally publishedYes

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Keywords

  • Cadmium
  • Calcium channel
  • Dihydropyridine
  • Dorsal root ganglion cell
  • Patch clamp
  • ω-Contoxin

ASJC Scopus subject areas

  • Neuroscience(all)

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